This invention relates to manifolds for servicing refrigeration, air conditioning, and heat pump systems, which in operation effect heat transfer through cyclically changing a refrigerant between liquid and vapor states.
Many air conditioning, refrigeration and heat pump systems utilize refrigerants to effect heat transfer. Typically, the refrigerant is from a class of fluids known as freon. The heat transfer is effected by compressing a refrigerant in its gaseous state to liquefy it and in the process release heat energy. In the case of refrigeration or air conditioning a heat exchanger dissipates the released heat to an ambient atmosphere. The liquid refrigerant is flowed to another heat exchanger which is in heat absorbing relationship with a space to be cooled. The refrigerant is allowed to expand and vaporize to absorb heat via the second heat exchanger.
In a refrigerator, for example, a compressor unit disposed outside a refrigerated compartment, is used to compress the refrigerant from its vapor state to a liquid state and thereby dispel heat to the ambient atmosphere. Liquid refrigerant is delivered to a cooling heat exchanger in communication with an atmosphere within the refrigeration chamber. The refrigerant is allowed to vaporize within the cooling heat exchanger and thereby absorb heat from the atmosphere within the chamber.
The systems which use refrigerant for heat transfer from time to time must be serviced by a process known as charging. With the charging process, a manifold is connected to the system being recharged and to a source of refrigerant. When the system is being fully recharged it typically is evacuated and then the refrigerant is delivered in liquid form via the manifold to the system. For top-off, the refrigerant is charged in its vapor state.
Heretofore, such recharging has typically used a manifold for recharging. The manifold has high side and low side outlets which are respectively connected to the high or liquid side and the low or vapor side of a compressor. For primary recharging, when the recharging is done properly, the low side outlet is closed, a source of liquid refrigerant is connected to an inlet to the manifold and the high side is charged to a desired level. Once the primary recharging has been completed, the high side or liquid outlet is closed and the vapor side is opened. Refrigerant is fed through a vaporizing restrictor connected in series with the manifold. The compressor is energized to cause it to liquefy vapor from the low side and deliver liquid refrigerant to the high side. Top-off is then achieved by delivering vapor to the low side of the system being charged.
Accordingly, there has been a need for a recharging manifold system which can effect primary recharging utilizing liquid refrigerant and top-off with vaporized refrigerant without use of a manifold and a restrictor in series with it.
In its preferred form, a mechanism embodying the present invention includes a manifold. The manifold has a housing defining an inlet and two outlets. One of the outlets is intended to be connected to the so-called high side of a system being charged, while the other outlet is intended to be connected to the so-called low side. The high side is that portion of the system being charged in which refrigerant is contained in its liquid state, while the low side contains refrigerant in its vapor state.
The manifold has an inlet for connection to a source of refrigerant which under current mandates is always in a liquid state. Internal passages in the manifold communicate the supply inlet with a state control arrangement embodying novel features of the present invention. Other internal manifold passages communicate the arrangement with the outlets. A pair of outlet control valves are provided, each associated with a different one of the outlets for selectively establishing and interrupting communication between manifold passages and the associated outlet.
The state control arrangement includes a capillary in parallel communication with a section of the inlet passage. A charging flow phase control valve is provided. The phase control valve has an open position allowing flow of liquid refrigerant from the inlet through both the passage section and the capillary to the outlets. The phase control valve has a closed position shutting off flow through the passage section while permitting flow through the capillary. When the phase control valve is closed, flow through the capillary results in the refrigerant being vaporized.
In a process of recharging a system, the novel and improved manifold is connected to the system to be charged. The high side and phase control valves are placed in open conditions. Refrigerant in liquid form is fed through the inlet opening thence through both the passage section and the capillary and then to and through the high side outlet to the system being charged to deliver refrigerant in liquid form. When it is desired to fill or to top-off with refrigerant in vaporized form, one simply closes the phase control valve and the high side outlet valve. The low side outlet valve is opened and further refrigerant flows from the inlet through the capillary where the refrigerant is vaporized and hence through the low side outlet into the system being charged. Concurrently the systems compressor is operated to top off the system high side while the input vapor tops off the low side.
When the system is used with refrigerants in older systems, top off is enhanced because the refrigerant is supplied in vapor form and the phase control valve is open.
Accordingly, the objects of the invention are to provide a novel and improved refrigerant manifold and a process of recharging systems utilizing refrigerant.